1. Field of the Invention
The invention relates to a method and apparatus for effecting the angular alignment of a plurality of angularly spaced shaped charges of a tubing conveyed well casing perforating gun to insure that none of the explosive charges are directed vertically upwardly in any non-vertical section of the well casing.
2. Description of the Prior Art
It is well known that any drilled well never proceeds on an exactly vertical path to a production formation. In fact, it is not unusual to have the well bore, and hence the well casing, enter a production formation at a substantial angle to the vertical, approaching a horizontal angle on the order of 15.degree.. If a conventional perforating gun were employed to effect the perforation of the well casing in any such non-vertical section, it is most likely that a plurality of the explosive charges carried by the gun would be directed almost vertically upwardly. Such vertically upwardly directed perforations in a well casing are highly undesirable, since they permit the ready flow of sand and other particulate material directly into the casing and present obvious problems insofar as the completion and production operation of the well are concerned. On the other hand, it is desirable that a plurality of axially and angularly spaced perforations be produced in the non-vertical section of the casing in order to facilitate the entry of well fluids into the casing in all but a vertically downward direction.
It is equally desirable from an economic standpoint that the perforating and gravel packing of the well casing be accomplished with a single trip of a combined perforating and gravel packing apparatus in the well. Such single trip apparatus is dislosed and claimed in the co-pending application Ser. No. 366,267 (BSC-76) filed Apr. 7, 1982, and assigned to the assignee of the instant invention. An essential element of such one trip perforating and gravel packing apparatus is the provision of an uninterrupted conduit extending from the gravel packing apparatus to the well head. Such conduit not only permits a detonating weight to be dropped on the perforating gun but also provides a path for the flow of well flushing and gravel packing fluids.
An apparatus for effecting the perforating of a well casing by a perforating gun suspended from a continuous conduit extending to the well head and permitting angular alignment of the explosive charges of the perforating gun so that no charges are disposed in a vertically upward direction in a non-vertical section of the casing, has not heretofore been provided in the prior art in tubing conveyed perforating guns.